Archetypes and Controls of Riverine Nutrient Export Across German Catchments

Elevated nutrient inputs challenge the health and functioning of aquatic ecosystems. To improve riverine water quality management, it is necessary to understand underlying biogeochemical physical processes, anthropogenic drivers their interactions at catchment scale. We hypothesize that spatial heterogeneity sources dominantly controls variability in-stream concentration dynamics among catchments. investigated mean nitrate (NO3−), phosphate (PO43−), total organic carbon (TOC) concentrations concentration-discharge (C-Q) relationships in 787 German catchments a newly assembled data base, covering wide range physiographic settings. linked metrics characteristics using partial least squares regressions random forests. found archetypal C-Q patterns with enrichment dominating NO3− TOC, dilution PO43− export. Both variance sites increased agricultural land use. argue subsurface denitrification can buffer high nitrogen cause decline depth, resulting chemodynamic, strongly positive patterns. Mean were related point sources, though low predictive power suggests effects unaccounted processes. In contrast, diffuse explained observed TOC levels positively abundance riparian wetlands, while hydrological descriptors important for explaining dynamics. Our study shows strong modulation by natural dynamics, only dominate across Germany.